1. Technical Field
The present invention relates to printed circuit boards in general, and in particular to a printed circuit board to be utilized in an optoelectric data processing system. Still more particularly, the present invention relates to an improved printed circuit board for coupling surface mounted semiconductor optoelectric devices.
2. Description of the Prior Art
Within most computer systems, a bus (or a group of buses) is typically the primary vehicle by which communication among electronic components takes place. Although there are different types of buses, in its most basic form, each bus is simply a series of electrical wires interconnecting various electronic components within a computer system. The electrical transmission characteristics of a bus are defined by the material properties of the bus, the physical geometry of the components, the clock speed of the signals, and the noise within the bus. Thus, both the limitations in materials and the limitations in electronic components contribute to the electrical transmission characteristics of a bus.
As computer systems become more complex, there is a continuing need to drive signals within a bus at a faster clock rate while at the same time minimizing power, noise, and electromagnetic interference. Most if not all of these requirements are satisfied by optoelectric computer systems. An optoelectric computer system is a computer system in which digital data signals are transmitted in both electrically conductive buses and optical buses (or pathways). Such a computer system may, for example, utilize semiconductor devices that have vertical cavity surface emitting lasers (VCSELs) serving as transducers for optoelectric exchange. One such semiconductor device that is now in commercial use is the HFBR-5303 VCSEL transceiver manufactured by Hewlett Packard.TM..
With a printed circuit board having optical pathways, it is important to ensure that optoelectric devices, as they are mounted on the printed circuit board, are sufficiently aligned with the optical pathways in order to provide reliable operation even if the optoelectric computer system is subject to vibration or shock that would otherwise shift the optoelectric devices out of alignment. Further, there may arise a need to accommodate for non-ideal alignment situations between optoelectric devices and optical pathways during manufacturing. In order to eliminate the above-mentioned problems, the present invention provides an improved method for coupling surface mounted optoelectric semiconductor devices on a printed circuit board.